Device for timing telephone calls



May 30, 1950 s. F. DUNNING DEVICE FOR TIMING TELEPHONE CALLS 5 Sheets-Sheet l Emily. E

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Original Filed April 21, 1945 L V L'LIVZ 0R 5. E 022 any Mi /Mm ATTDJEZVEY W 9 1950 s. F. DUNNING 2,509,489

DEVICE FOR TIMING TELEPHONE CALLS Original Filed April 21, 1945 3 Sheets-Sheet 2 INVENTOR 51E Dunning ATTORAEEY May 30, 1950 S. F. DUNNING DEVICE FOR TIMING TELEPHONE CALLS Original Filed April 21, 1945 3 Sheets-Sheet 5 INVENTOR 61E DLU bI LL W ATTORNE Y Patented May 30, 1950 DEVICE FOR TIlVIING TELEPHONE CALLS Sanford Frank Dunning, Glen Ellyn, Ill., assignor to American Telephone and Telegraph Company, a corporationof New York Original application Amt. 21, 1945, Serial No.

589,606., new PatentNo. 2,492,381, dated Decemher 25,1949. Divided tember 6,1946, Serial 7' Claims;

This invention relates to timing devices and particularly to a method and means for timing the duration of a telephone call. This application is a division of my pending application Serial No. 589,606, filed April 21, 1945, now PatentNo.

2,492,381 dated December 27, 1949.

The present invention resides in a. timing device connected With a cord circuit, in a telephone switchboardand under-the control of the message register key. or other key whereby a signal will be given to the operator toindicate the termination of a pre-fixed interval of time during which a telephone conversation has been maintained over the lines connected" to the said. cord circuit.

The form of the device in which this invention is embodied, and its mode of operation, will be clearly understood from the following description when read in connection. with the. attached drawing of whiclrFigure 1 is a view in perspective of the timing device; Fig. 2 is" a side view of thesaid device, with a portion shown as a crosssection; and Figs. 3 and 4". are schematic drawings of some of the cord circuits with which the said timing devi'cexmay be employed.

The timing device, in which thisinvent'ion resides, employs a rotating drum which has thereon a spiraled groove extendingfrom one. end" oi; the drum to the oth'erpthe speed of rotation of the drum and the length of the groove being such thatif a rider engages the groove at one end of the drum, it will be carried; to the otherend of the drum in a given interval of time. By the provision of suitable-contacts a circuit through a signal device, such as a lamp, will be closed when the rider has traversed the length of the drum.

That device and itsmode of operation'willbe clearly understoodby referring to Figs. 1 and" 2' in which the same reference numeralshave been employed to indicate the same parts; At the top of the device there is represented" an electric motor I which is suitably mounted upona platform 2 fixedly connected to the ring 3 having a clamping means; 4" by which the entire device may be supported from the inside of the top or the side of a switchboard section. The motor IL is geared to the shaft 5 and at the lower end thereof is" another gear Ewhich meshes" with a gear- F that is" fixedly connected to the shaft 81 The. shaft 8, which hollow, is supported by the bolt 9" which is rigidly attached to the platform at I, and a drum lflfls. attachedto the shaft 8 so as to be rotated, thereby. shown";

The drum. as there is cylindrical in form and has a spiraled and this application Sep- 2 groove extending from one end to the other end thereof. The ends 12 and I3 of the cylinder, as shown in Fig. 2 are of insulating material, but the upper end is has thereon. a plate it which is of electrically conducting material. The ma- Jor portion of the side wall of, the cylinder I15 may be 01 either metallic or non-metallic material. If metallic, as shown in the drawing, that section should be insulated from the plate i l at the upper end of the drum for a purpose which will be later described.

The spiraled groove starts, as shown in the figures, at the lower end of the cylinder and extends up to and includes the plate 1 1' at the top; Beneath the drum, and supported by the bolt 9'; is a guide plate It having therein a plurality of slots such as ii of Fig. 1, the purpose of which is to guide the rods which support the riders that engage the groove of the drum. Each of those rods, such as It, is attached to an armature such es IQ of a magnet 26. The rider 2|, which is shown in the form ofa disc, is rotatable andslid able upon the rod l8, and, when not in engagement with the groove" of thefdrum, rests upon a collar 22 which is held. in position bya nut 23 at the bottom of the rod. The normal position of the rod IB is such as to holdthe rider away from the side wall of the drum. Upon the attraction of the armature is by the energiza'tion of the magnet 26, the rod f8 will be moved toward the drum to such extent asto bring the rider into engagement with the groove upon the drum, the position of engagement thereon being determined by the adjustment of the nut 23. Therods l8 are designed to move in planes" that extend'substan tially'through the axis of the drum, and they are maintained in that position, that is, they are prevented from swaying laterally bythe slots IT in the guide plate It. The rider'ii, upon its engagement with the grooveoi the drum, will be caused to moveupwardly upon the rod l8 and will continue thus to move until it reaches the plate [4 where the groove terminates;

When the rider comes to rest at theplate M; which it will do in a pre-fixed length of time, it will cause the closing of a circuit containing av lamp or' other signalling device which will indicate to an operator that a call has continued for that length of time. The manner in which that is accomplished will be presently described in connection with Figs. 3' and 4 which show the connection of the timing device with twodifferent types of. cord circuits. Before passing tothe. consideration of those figures,- it is desiredto point out that the apparatus just described engages a bracket 28. A terminal block 29 is provided for the terminals of the circuit of the motor I. The platform 2 also carries a plurality of contacts such as 38 and 3|, which are connected to the magnets such as 20 to provide means for connecting the timing device to the cord circuits of a position.

Having in mind the foregoing description of the timing device and of its mode of operation.

the manner in which the device is employed by an operator will be described, first, in connection with a cord circuit employed in two-party ticketed operation, and then in, connection with a cord circuit for message register operation.

In Fig. 3, P1 and P2 represent the answering and the calling plugs of the circuit. Upon receiving a call, the operator inserts the plug P1 in the jack J1 and answers in the usual manner. Thereupon, the plug P2 will be inserted in the jack J2 of the called partys line which will effect the operation of relay R1 and the lamp'Ll will light; When the called party answers the telephone, relay R3 will be operated and, thereupon the lamp L1 will be extinguished. The operation of relay R1 will apply the voltage of the battery B1 to the relay R2 which, however, will not be operated until the key K1 is operated. Since the parties are then in conversation, the operator will operate the key K1 which causes the operation of relay R2 and that in turn will energize the magnet 20 of the timing device. The attraction of its armature will swing the rod 88 inwardly toward the drum H and thereby will bring the rider 2| into engagement with the groove of the drum. The rider will then travel upward on the rod l8 until it comes into engagement with the plate [4 upon the upper end of the drum. Thereupon a circuit will be established that extends from the battery B2 to the grounded plate 14 and includes the lamp L2, rod I8, and the rider 2|. The lighting of the lamp indicates to the operator that the conversation has continued a given length of time, say five minutes. There upon the operator will again operate the key K1 which reduces the current through the magnet 20 so as to cause the magnet to be de-energized and thereby to permit the rod It to move the rider 2| out of engagement with the groove of the drum. The rider will thereupon fall to the bottom of the rod and since the key K1 is closed only momentarily, and is not now open, sufiicient current will now flow through the magnet it to attract its armature and to bring the rider 2! again into engagement with the groove of the drum at the low point thereon. Thereafter the rider will continue to rise along the rod I8 and to function in the manner heretofore described. Upon completion of the call, which will be evident by the lighting of the lamp L1 the operator will pull the plug P2 from the jack J2. That will release relays R1 and R2 which, in turn, will release the timing device and restore it to its initial position for subsequent use.

The manner in which the invention is employed in connection with a message registering circuit is shown in Fig. 4, Upon the receipt of a call, the plug P3 in inserted in the jack J3 which has a, message register connected to the sleeve 4 thereof. The operator will thereupon insert the plug P4 in the jack J4 of the called partys line thereby operating relay R4 and lighting the lamp L4. As soon as the party answers, relay R5 will operate, thereby extinguishing the lamp. Whe the operator observes that the called party has answered, she will then momentarily depress the message register key K2, the operation of which operates relay Re which in turn closes a path through its locking contact to operate relay R1 which, together with all other relays and apparatus below the dotted line AA is common to a plurality of cord circuits. Relay R1 does not operate however until the key K2 is released,

since it is shunted by direct ground through the key. The operation of relay R7 removes ground venting the operation of a second relay such as Re by the operation of another message register key. Relay R7 also operates relays R3 and R9 and R10 in turn. The operation of relay R10 releases relay R3 and in turn relays R9 and R10. The operation and release of the group of relays R8 to R10 provides 3 consecutive time intervals for unlocking the message register, operating the message register and releasing the common circuit which, as stated, is that shown below the line AA. v When relay Re operated it connected relay R11 across the tip and ring of the circuit. Relay R11 is operated'by current from the battery B41 and ground, through the repeating coil. The operation of relay Re also extends the sleeve of the cord to the contacts of relays R8 to Rio which, it should be stated, are of slow-releasing type. When the operation of the circuit has progressed to the point where relay Rs has released but relays R9 and R10 are still operated, voltagefrom the battery B3 which is of the order of 39 volts, is connected to the sleeve of the answering plug to operate the message register 32. Relay R9 has a minimum releasing period of 0.5 second to insure that the'register will operate and lock. Also, during the releasing time of relay R9 ground is connected to relay R13 in the cord circuit which operates and locks to ground through the winding 20 of the magnet of thetimin g device. The latter operates when ground is removed from the make contact of relay R10. When relay R9 is normal, relay R10 is in the process of releasing and the ground which holds relays Re and R7 operated'is removed and they accordingly release. Relay Rio is slow'releasing' to insure that the latter relays will have adequate time to restore.

As has been described heretofore, when the 1 magnet 20 of the timing device is energized the rider will be brought into engagement with the rotating drum and will continue to rise until it reaches the end of the groove in the metallic disc at the upper end of the drum which, for example, may occur at the end of the five minutes. Thereupon, the lamp L3 lights. When the operator sees the lamp lighted, she will momentarily depress the key K2 provided the super visory lamps L4 and L5 are still dark.. That operates relay Re and starts the control circuit functioning.

The control circuit, which as stated is that portion of the figure below the dotted line A-A, operates exactly as before, except that the relay R12 is operated from the timer ground. The latter puts ground on the sleeve during the releasing time of the relay Ra. That unlocks the message register, by shunting its winding, and the same shunt releases the cut-off relay of the lin i cu t which, tho gh not shown hefig- 1 .1 is t he understood t be present the eir,- cul Tha oper tion o ne t thes ound and battery of the line relay to thetip and ring of t e; in which te ds t produce an acou t c disturbancenc de to m n mize such disturbance. the va ietal netwo k 3.3 is hrovided. .If torvany reason the contacts .oi relay Rs failto connect the varistors across the line, the winding of relay B11 willalso be open andnwill accordingly not be operated. Under that condition the shunting ground will be open and accordingly the the guarded disturbance will i not be applied.

When relay Re is ::normal, ground is applied tothe windingof relay Bra in the cord circuit which holds the latter but releases the timing device by shunting the winding of the magnet 20. Accordingly, ground is immediately removed from the circuit in which the rider 2| of the timer is included and accordingly relay R12 is released. As a result of that operation, the circuit from the battery B3 to the winding of the message register is closed, which causes the operation of the message register and thereafter the operation proceeds as hereinbefore described. It is desirable to point out that uponthe release of the timing device the rider 2i drops to the bottom of the rod l8 and, upon subsequent operation of the said device the rider was again brought into engagement with the drum 1 I, thus starting the timing of the next prefixed interval of time.

It is desirable to point out that each of the magnets is individual to and connected with one of the cord circuits of an operating position so that by the provisions of the required number of magnets a single timing device will take care of the timing operations of all the cord circuits of an operating position of the switchboard. It will, of course, be obvious that various modifications may be made in the structure of this timing device without departing from the scope of the invention. For example, the drum II, as shown in Figs. 1 and 2 could be made entirely of plastic or other insulating material except for a ring or a plate of electrically conducting material at the upper end thereof by which the circuit is closed when the rider reaches the upper end of the drum.

If it is desired to close the circuit of the indicating lamp at successive intervals of time, say at the end of live minutes and again at the end of ten minutes, such result could be accomplished by a drum having a plurality of metallic rings or plates operated by insulating sections, the entire drum of course being grooved so that the rider will travel continuously from one end of the drum to the other, and will make contact with one of the metallic rings or plates at the end of the first interval of time and will then continue to travel along the drum until the second metallic ring or plate is reached at the end of the second interval of time. It is to be understood, of course, that such metallic rings or plates should be connected to ground in order to effect the closing of the circuit, that includes the signaling device, when the rider comes in contact with the ring or plate. In the form of the invention shown in Fig. 2, the plate I4 is conductively connected to the shaft 8, which in turn is conductively connected to the supporting frame of the timing device which is grounded In addition to the types of circuits shown in Figs. 3 and 4, the invention may be used in connection with other types of circuits, such, for

example, as thei ord circuit employed with coin:- collect telephones. I11 the latter type of circui rtheztiming device will light the associated lamp attheendof a=fiveminute period, or Otherpre- :fixed interval of time. If the call is still in progress, the operator will open the talk-key of that circuit and ask for the deposit oian additional .coin. Thedetection of the deposit of the coin,.andcits collection, is evidenced by a tone in theoperators headset, in the usual manner. The timing device will be restored to its initial position in order to startagain the timing of the next five minute period. .At the conclusion of the callxthe trunkrcord is removed whichre leases the relay such as R2 associated with the -:timing..device land cresets that device for sub sequent operation. 1 i a While this invention has been disclosed as embodied in a particular form and'arrangement' of parts, it .is capable of embodiment in other and diiferent forms without departing fromthe spirit and scope of theappended claims.

What .is claimed :is:

1. A devicefortiming the duration of a tele.- phone call: including a rotatable :drum mounted upon a verticalaxisand having thereon a spiral groove extending around the cylindrical wall of said drum from the top to the bottom thereof, the said drum having at the top thereof a layer electrically conductive and insulated from the remainder of the drum, means to rotate the drum at a uniform speed, a magnet, the armature of which has an extension member which is substantially vertical and parallel to the axis of the drum when the magnet is energized, and an electrically conductive rider rotatably and slidably mounted upon the said extension member and arranged to engage the groove upon the drum whenever the magnet is energized whereby it will be moved upward upon the said extension member by the rotation of the drum and will drop to the bottom of said member when the magnet is deenergized.

2. The invention of claim 1 characterized further in that the speed of rotation of the drum and the length of the groove are such that the rider will travel from the bottom of the drum to the electrically conductive layer at the top thereof in a pro-fixed interval of time.

3. A device for timing the duration of :a telephone call including a drum having thereon a spiral groove extending around the cylindrical wall of the said drum from the top to the bottom thereof, the said drum having at the top thereof a layer electrically conductive and insulated from the remainder of the drum, means to rotate the drum at a uniform speed, a plurality of magnets, each of the armatures of which has an extension member which is substantially vertical and parallel to the axis of the drum when its corresponding magnet is energized, and a plurality of electrically conductive riders each individual to one of said armatures and rotatably mounted upon the extension member thereof to engage the groove upon the drum whenever the magnet is energized whereby the said rider will be moved upward upon the said extension by the rotation of the drum and will drop to the bottom of the said extension member when the magnet is deenergized.

4. A device for timing the duration of a telephone call including a rotatable cylindrical member having a spiral groove thereon, a portion of which member is electrically conductive and insulated from the remainder of the said member,

an electrically conductive rider slidably mounted and adapted to engage the said member, the speed of rotation of which and the length of the groove path being such as to cause the said rider to travel into engagement with the conductive portion of the said member within a pre-fixed interval of time.

5. The invention defined by claim 4 further characterized by the inclusion of electromagnetic means to move the said rider into engagement with the said grooved member.

6. A device for timing the duration of a telephone call including a cylindrical drum a portion of which is electrically conductive and having a spiral groove formed in the curved wall thereof, a vertical shaft to which the said drum is rigidly attached, means to rotate the said shaft at the uniform speed, a slidable rider of electrically conductive material and adapted to engage the groove upon the said drum, a rod adapted to support the said rider and to permit its movement rotatably and longitudinally upon the said rod, a magnet having an armature associated therewith, the said armature rigidly supporting the said rod and arranged to swing the said rod inward and outward substantially ina plane passing through the axis of the shaft of the said drum. 7

7. A device for timing the duration of a telephone call including a rotatable cylindrical drum having a spiral groove upon' the curved wall thereof and extending from one end of the drum to the other, the said groove terminating in a section of electrically conducting material which is insulated from the remainder-of the said drum, an electrically conductive rider adapted to engage the groove of the drum near one end thereof, and to be carried by the rotation of the drum to the said section of electrically conducting material, a rod upon which the said rider is slidably supported and electromagnetic means to move the said rod to bring the said rider into engagement with the groove upon the said drum.

SANFORD FRANK DUNNING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,554,340 Gent Sept. 22, 1925 2,029,667 Maxwell Feb. 4, 1936 

